Question about replacing exhaust manifold and riser on merc 3.0

[chefg1124]

I have had this boat just for this season. Previous owner had it stored on land after ever use by a marina but not sure if the engine was flushed after every use. I personally flush after every use but being a 2001 I don't think that will stem any corrosion that has already been done in the past 11 years. I do not believe the manifold or riser was ever replaced. I have no issues at the moment and would like to avoid them if at all possible. I was inspecting the engine and noticed a little rust were the riser meets the manifold. I am going to order a new riser, gasket, bolts, etc but my question is with the length of time since anything has been replaced or inspected should I expect the manifold to need replacing as well? I don't want to not order it and find out I need one only to further delay my next outing by having to wait for UPS. On the other hand I don't want to spend a needless $200 on a manifold to find out that its fine. If I take it off to inspect it and its ok the boat will be rendered useless until I get a new gasket and this weekend is shot. Is it common to replace in tandem or is it specific to every boat and the way its stored and used? Thanks for the advice.

 

[Don S]

Re: Question about replacing exhaust manifold and riser on merc 3.0

Is this a salt water boat? If so, just pull the riser, clean and inspect the gasket surfaces of both. If you aren't sure, post some pictures.

 

[chefg1124]

Re: Question about replacing exhaust manifold and riser on merc 3.0

sorry yes. meant to mention it is a salt water boat and it was prior to me purchasing it as well. I am planning on ordering the riser and gasket set. If I go off the fact that's its a 2001 boat, original engine and mercruiser 3.0 the part I found online should match? I would like to order but I am at work. From what i found online its a Mercruiser 12076a. can anyone confirm this? 4 cylinder 3.0 135hp 2001 mercruiser.

 

[Don S]

Re: Question about replacing exhaust manifold and riser on merc 3.0

Merc goes by SN range, not year. Do you have the serial number handy?

 

[chefg1124]

Re: Question about replacing exhaust manifold and riser on merc 3.0

I do not and I don't think my wife will be too inclined to climb in and find it for me. I am off tomorrow so I will jot it down and order a riser before i take her out. where should i look once I have the s/n? its by the starter right? I think i read that on here someplace.

 

[Jiminthekeys]

Re: Question about replacing exhaust manifold and riser on merc 3.0

Yeah there should be a plate by the starter. Also on the sticker on the flame arrestor ontop of the carb.
I would definetly check the water passage thickness on the manifold side that mates up with the riser. You want I believe at least .25 inch thickness between the water passage and exhaust passage at the mating surface.

I just did mine (2007) and both were gone. And my boat is always flushed religiously.

I purchased from ********** and got both for $500 after a 10% disc code from retail me not. Came with all gaskets, new hardware, and new fuel line. Iboat prices are comparable as well...